Add CTS tests for EthernetNetworkProvider changes am: 69e9db5057

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/18591833

Change-Id: I5bfb66b2fa7ec2388756b5e14213b8380e8f9d56
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>